Well pump



R. P. VINCENT Jan. 22, 1963 WELL PUMP 2 Sheets-Sheet 1 Filed March 5, 1961 IN VEN TOR.

e p7 ATTORNEY R. P. VINCENT Jan. 22, 1963 WELL PUMP Filed March 3, 1961 Fig. 4

Fig. 3

REN/C R VINCENT INV EN TOR.

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ATToR/vEY/ 3,074,352 WELL PUMP Renic P. Vincent, Tulsa, Gide., assigner to Pan American Petroleum Corporation, Tulsa, Okla., a corporation of Delaware Filed Mar. 3, 1961, Ser. No. 93,034 l Claims. (Cl. lt3l79) This invention 'relates to a novel pump design adapted for use in the pumping of oil weils. More particularly, it is concerned with a pump design especially useful in the pumping of wells formed by slim hole drilling, i.e., wells completed without tubing,

ln recent years considerable interest has been shown in slim hole drilling and completions because of the substantial savings in drilling and equipment costs. With the introduction of such practice, however, a number of problems have been created, one of the more important being the design of a pump capable of operating etiiciently over extended periods of time under slim hole producing conditions.

Pumps for slim hole wells using hollow sucker rods as a conduit for lifting the iluid to the surface have been previously employed, but have been unsatisfactory because of the hydraulic forces inside the hollow rods which act upwardly on the bottom of the pump plunger, causing the rods to buckle helically, or to corkscrew on the pump downstroke.1 Furthermore, with the rods corkscrewed on the pump downstroke, excessive wear occurs, not only on the rods but also on the conduit surrounding the hollow rods. In the case of slim hole or multizone wells, this conduit is the well casing. Excessive wear can cause holes, making expensive remedial meassures necessary. During the pump upstroke, the sucker rod straightens. The repeated helical bending and straightening causes fatigue of the hollow rod connections and breakage occurs.

It is advisable, in order to eliminate the conditions which cause buckling, to lift the heavier well iiuid, such as oil and/ or water, up the annulus between the hollow sucker rod string and the conduit and to provide an escape to the surface for the gaseous lluids through the string of hollow sucker rods. ln this system, the high hydraulic pressure on the outside of the hollow rods resulting from the head of duid, provides a straightening force on the rods on both the upstroke and the downstroke.

There are pumps available which permit production as described above. Such equipment, however, employs a sliding crossover seal which permits gaseous iiuids to llow around the pump into the hollow rods and, at the same time, transfers the uids owing from the variablevolume chamber of the pump into the annulus between the hollow rods and the surrounding conduit. The disadvantage of this system is that the length of the pump is doubled since the sliding seal crossover arrangement is, by necessity, located above the pump and must be of equal length to accommodate the full pump stroke. Also, the full hydraulic head of fluid is exposed to this sliding seal on both the upstroke and downstroke of the pump. This leak reduces the efficiency of the pump and will also, during long shut-down periods, allow the eduction conduit to drain.

Also, the design of these pumps has been such that sand and other solids tending to collect above the pump seat in time cause the pump to fail. A further difficulty encountered with pumps of this type is gas locking. If gas accumulates in the working barrel of a pump equipped with conventional ball-and-seat valves, there is a possi- 731 ge AIME Transactions, Petroleum Brauch, vol. 210, pp.

i tr f bility that the pump will gas lock. To expel the gas, the pressure in the gas zone on the downstroke must be high enough to overcome the presure of the liuid operating on top of the valve. Only then will the valve open. If the stroke is too short, or if too much gas has accumulated, operation of the pump does nothing more than compress and expand the gas in the working barrel and no oil is lifted. Lengthening the stroke or increasing the pump ing speed can be used to overcome this problem.

it is an object of my invention to provide a hollow sucker rod pump consisting essentially of a single section and in which the rod is not subjected to buckling action because during the downstroke there is no net hydraulic upward force exerted thereon. lt is a further object of my invention to provide a pump capable of operating over extended periods with sand or similar solids in the pumped fluids without damage to the pump itself. It is another object of my invention to provide a pump that can handle gases and liquids simultaneously without gas locking.

For a better understanding of my invention, reference is made to the accompanying drawings in which:

iGURE l is an elevational sectional view of the coinplete pump mechanism showing the latter in the downstroke position;

FIGURE 2 is a fragmentary sectional view, illustrating a modification of the gas-oil separator portion of the Pump;

FIGURE 3 is a plan View of FlGURE l taken along line 3-3;

FlGURE 4 is a plan view of FIGURE 2 taken along line 4 4; and

FlGURE 5 is a sectional view of another type of valve `design that may be substituted for the lower traveling valve shown in FIGURE l.

Referring again to FGURE l, a well casing l0 has at the lower end thereof a pump seat l2. A pump assembly ll, including a working barrel i6 and a head i8 having ports Ztl, rests in pump seat l2. Guidepiece 22, which is a part of head 18, holds hollow rod 24 in alignment with the axis of the pump. The t of rod 2d with the guidepiece need not be fluid-tight. At the lower end of rod 24, a piston or plunger 26, sized so as tc slide freely within working barrel 16, is threadedly engaged to rod 24. Permissible clearance between the plunger and working barrel may range from about .0005 to about .005 inch. At the base of barrel lo is a standing valve 2S. In plunger 26 are a plurality of annularlyspaced longitudinal passages 3G which terminate at the beveled face of plunger 26, which forms a seat 32 for traveling valve 34. Stop 36 prevents further upward movement of valve 32. Above stop 36 is a second standing valve cornprising an annular member 33 resting on auxiliary valve seat 4@ which lits loosely about rod 24. Auxiliary valve seat dll, in turn, forms a seal with valve seat 42. Valve 3S preferably does not form a fluid-tight seal with rod 24 and auxiliary valve seat dit.

ln FIGURE 2, an oil-gas separator may be substituted for plunger 26 of FIGURE l, wherein a plunger Si! carried on rod 24 is sized to slide freely in working barrel i6. The lower end of rod 24 has a closure 52 which, with standing valve 54, forms chamber 56 having port 5S communicating with a plurality of spaced vertical passageways 60. These passageways terminate at the top side of plunger Sli, having beveled face 62. Passageways 6i) do not surround rod 2e, but preferably are arranged in a pattern such as that shown in FIGURE 4. Also, in plunger 50, and substantially opposite passageways dit, is a single passageway 64 extending from the base of plunger S0 above closure 52 and communicating with the interior of rod 24 via port 66.

In FIGURE 5, a plunger 7i?, having vertical annularly disposed passageways 72, reciprocates in working barrel 16. The lower end of hollow rod 24 has an externally threaded portion 76 tbreadedly engaged to internally threaded portion 78 of a downwardly extending recess in plunger 7h.

In operation, referring to FIGURE 1, well liuids enter pump assembly 14 through bottom standing valve 2S on the up-stroke. Gas separates from the liquids, and the bulk thereof flows upwardly into hollow rod 24. Gas breakout is assisted on the downstroke of plunger 26 which serves to agitate the liquids in the lower end of working barrel 16. During this same downstroke, liquids, together with small amounts of gas, ow upwardly through passageways 30 in plunger 26 and lift traveling valve 34 olf seat 32. Stop 36 limits the distance traveling valve 34 moves along rod 24 and promotes faster closing of the valve at the start of the upstroke. Also, at this time, there is a tendency for tiuids below plunger 26 to how out the oriice, seating the valve 28, causing the latter to seat or close, thus tending to drive any remaining uids into hollow rod 24 and into passage ways 30. On the upstroke, valve 34 seats in beveled face 32 to trap the liquid above it. The rising liquid unseats standing valve 3S. After passing through the upper valve, the liquids discharge through ports into the annulus between slim hole casing 10 and hollow sucker rod 24. Guidepiece 22, at the head of pump assembly 14, holds the hollow rod in alignment with the axis of the pump and improves the operation of the upper standing valve 38.

In place of the upper standing valve shown in FIGURE 1, a single element valve similar to traveling valve 34 may be used. The upper standing valve preferably does not form a huid-tight seal between hollow rod 24 and auxiliary valve seat 42. This structure permits a small quantity of oil above the pump to leak into pump barrel 16 above the piston. By this slight leak, a gas locking condition can be corrected when enough liquid has owed into the working barrel to unseat the upper standing valve and displace the gas via ports 2G at the top of the pump stroke. Gas locking tendencies are further reduced owing to the loW head space between the piston and the upper standing valve. Where severe gas locking is not a problem, the upper valve may be close-fitting to prevent leak-back. Also, the bottom standing valve may be omitted with the close-titting valve because the oil in the casing Will not leak out through the pump during shut in periods.

As previously indicated, a modification such as that shown in FIGURE 2 may be substituted for the plunger design of FIGURE 1. Gas and oil in working barrel 16 below plunger 50 separate, with the gas rising through passage 64 and entering hollow rod 24 via port 66 above closure 52. The well liquids pass through standing valve 54 in rod 24, ow through the rod via port S8 and passages 60 into working barrel 16 above the plunger. Above plunger 50 the pump structure employing the modification shown in FIGURE 2 may be identical with that illustrated in FIGURE l.

A further modilication of a suitable plunger structure is shown in FIGURE 5 in which well uids enter the open end of working barrel 16, separated gas being vented up hollow rod 24. Well liquids on the downstroke travel upwardly through passages 72 in plunger 79, unseating ball valves 74 and filling the annulus between barrel 16 and rod 24. On the upstroke of plunger 70, valves 74 close carrying annulus liquids upwardly through the barrel into an upper structure which may again resemble that shown in FIGURE l.

By the foregoing description and drawings, it will be apparent to those skilled in the art that the present invention provides a simple and eltcient slim hole well pump capable of handling gases and liquids. While this pump mechanism is designed specifically for slim hole wells having small diameter pipe cemented in the well, it

will be apparent that the principles illustrated by the design described herein Will be applicable to many other environments without departing from the scope of this invention.

I claim:

l. A pump having in combination a barrel,

a hollow rod member extending into said barrel,

a guidepiece at the upper end of said barrel adapted to hold said rod member parallel and concentric with the longitudinal axis of said barrel while said rod member reciprocates therein,

a plunger in said barrel, said rod member carrying said plunger and communicating with the remote side of said plunger,

valve means in said barrel spaced above said plunger and dening a variable-volume chamber therebetween,

an outlet communicating with said chamber and with the space between said hollow rod and said guidepiece, communication through said outlet being controlled by said valve means,

passage means in said plunger for the ow of fluids through said plunger, and

means on the side of said plunger adjacent said chamber for preventing the downward ow of liquids through said plunger on the upstroke of said plunger.

2. 'Ihe pump of claim l in which said last named means comprises a travelling valve on said rod member which prevents the downward flow of liquids through said plunger, said travelling valve being adapted to form a fluidtight seal with said plunger only on the upstroke of said plunger.

3. The pump of claim 2 in which said rod member carries a stop between said travelling valve and the valve means cooperating with said outlet.

4. The pump of claim l in which said plunger has a plurality of spaced passages running through said plunger and into said chamber.

5. The pump of claim 1 in which there is a valve means in the lower end of said barrel on said remote side of said plunger, said valve means being adapted to open on the upstroke and close on the downstroke of said pump.

6. The pump of claim l in which said outlet means comprises a valve seat between said Variable-volume `chamber and said guidepiece and a standing valve on said rod member adapted to form a seal with said seat.

7. In a pump, the combination comprising a barrel,

a hollow rod member extending into said barrel,

a. guidepiece at the upper end of said barrel adapted to hold said rod member parallel with the longitudinal axis of said barrel while said rod member reciprocates therein,

outlet means in said guidepiece,

a plunger in said barrel having an outside diameter slightly less than the inside diameter of said barrel, said rod member carrying said plunger and communicating with the remote side thereof,

a valve seat in said barrel cooperating with said outlet means spaced above said plunger and a standing valve surrounding said rod member adapted to form a seal with said valve seat to define a variable-volume chamber between said valve seat and said plunger,

passage means in said plunger for the ow of fluids through said plunger,

means on the side of said plunger adjacent said chamber for preventing the downward ow of said liquids through said plunger on the upstroke of said plunger.

8. A pump having in combination a barrel,

a hollow rod member extending into said barrel,

a plunger in said barrel, said rod member carrying said plunger and communicating with the remote side of said plunger,

valve means in said barrel spaced above said plunger and dening a variable-Volume chamber therebetween,

an outlet communicating with said chamber and with the exterior of said chamber, communication through said outlet being controlled by said valve means,

passage means in said plunger for the ow of uids through said plunger, and

means on the side of said plunger adjacent said chamber for preventing the downward flow of liquids through said plunger on the upstroke of said plunger.

9. In a pump, the combination comprising a barrel,

a hollow rod member extending into said barrel, a

plunger in said barrel and carried by said rod member, the latter communicating with the remote side of said plunger,

valve means in said barrel spaced above said plunger and dening a variable-volume chamber therebetween,

an outlet communicating with said chamber and with the exterior of said chamber, communication through said outlet being controlled by said valve means,

passage means in said plunger for the flow of uids through said plunger, and

a check valve associated with said plunger for preventing the downward flow of liquid through said plunger on the upstroke of said plunger.

10. `In a pump, the combination comprising a barrel, 30

a hollow rod member extending into said barrel,

a plunger in said barrel and carried by said rod member, the latter communicating with the remote side of said plunger,

valve means in said barrel spaced above said plunger and defining a variable-volume chamber therebetween,

an outlet communicating with said chamber and with the exterior of said chamber, communication through said `outlet being controlled by said valve means,

a passage means (1) in said plunger communicating with the interior of said rod member and with said remote side,

a conduit leading into said plunger from said remote side,

a passage means (2) leading from said conduit through said plunger and into said variable-volume chamber, and

a check valve in said conduit for preventing the downward ow of liquids through said plunger on the upstroke of said plunger.

References Cited in the le of this patent UNITED STATES PATENTS 237,801 Bakewell Feb. 15, 1881 913,123 Gleason Feb. 23, 1909 1,104,962 `Clark July 28, 1914 FORETGN PATENTS 1,157,051 France Dec. 23, 1957 

1. A PUMP HAVING IN COMBINATION A BARREL, A HOLLOW ROD MEMBER EXTENDING INTO SAID BARREL, A GUIDEPIECE AT THE UPPER END OF SAID BARREL ADAPTED TO HOLD SAID ROD MEMBER PARALLEL AND CONCENTRIC WITH THE LONGITUDINAL AXIS OF SAID BARREL WHILE SAID ROD MEMBER RECIPROCATES THEREIN, A PLUNGER IN SAID BARREL, SAID ROD MEMBER CARRYING SAID PLUNGER AND COMMUNICATING WITH THE REMOTE SIDE OF SAID PLUNGER, VALVE MEANS IN SAID BARREL SPACED ABOVE SAID PLUNGER AND DEFINING A VARIABLE-VOLUME CHAMBER THEREBETWEEN, AN OUTLET COMMUNICATING WITH SAID CHAMBER AND WITH THE SPACE BETWEEN SAID HOLLOW ROD AND SAID GUIDEPIECE, COMMUNICATION THROUGH SAID OUTLET BEING CONTROLLED BY SAID VALVE MEANS, PASSAGE MEANS IN SAID PLUNGER FOR THE FLOW OF FLUIDS THROUGH SAID PLUNGER, AND MEANS ON THE SIDE OF SAID PLUNGER ADJACENT SAID CHAMBER FOR PREVENTING THE DOWNWARD FLOW OF LIQUIDS THROUGH SAID PLUNGER ON THE UPSTROKE OF SAID PLUNGER. 